EP1302212A2 - Forehead support for a facial mask - Google Patents

Abstract

A device for delivering a supply of gases to a user comprising: a patient interface, in usein fluid communication with said supply of gases, a forehead support adapted to pivotabout said interface and in use rest on the forehead of a user and configurable at least inan adjustment mode for selecting a desired fixed relation and a secured mode for securingsaid desired fixed relation. In one embodiment of the patient interface a mask sealsagainst the face of said user and deliver said gases to the nasal cavity and/or oral cavityand/or throat of said user without substantial pressure on the users face.

Description

FIELD OF INVENTION
• This invention relates to patient interfaces particularly though not solely for use indelivering CPAP therapy to patients suffering from obstructive sleep apnoea (OSA).
BACKGROUND OF THE INVENTION
• In the art of respiration devices, there are well known variety of respiratory maskswhich cover the nose and/or mouth of a human user in order to provide a continuous sealaround the nasal and/or oral areas of the face such that gas may be provided at positivepressure within the mask for consumption by the user. The uses for such masks range fromhigh altitude breathing (i.e. aviation applications) to mining and fire fighting applications,to various medical diagnostic and therapeutic applications.
• One requisite of such respiratory masks has been that they provide as effective sealagainst the user's face to prevent leakage of the gas being supplied. Commonly, in priormask configurations, a good mask-to-face seal has been attained in many instances onlywith considerable discomfort for the user. This problem is most crucial in thoseapplications, especially medical applications, which require the user to wear such a maskcontinuously for hours or perhaps even days. In such situations, the user will not toleratethe mask for long durations and optimum therapeutic or diagnostic objectives thus will notbe achieved, or will be achieved with great difficulty and considerable user discomfort.
• US Patent No. 5,243,971 and US Patent No. 6,112,746 are examples of prior artattempts to improve the mask system. US Patent No. 5,570,689 and PCT publication No.WO 00/78384, and US Patent No. 6,119,693 are examples of attempts to improve theforehead rest.
SUMMARY OF THE INVENTION
• It is an object of the present invention to attempt to provide a patient interfacewhich goes some way to overcoming the abovementioned disadvantages in the prior artor which will at least provide the industry with a useful choice.
• Accordingly in one aspect the present invention consists in a patient interface, inuse in fluid communication with said supply of gases,
     a forehead support adapted to pivot about said interface and in use rest on theforehead of a user and means for securing said forehead support in a substantially fixedrelation to said interface and configurable at least in an adjustment mode for selecting adesired fixed relation and a secured mode for securing said desired fixed relation.
• Preferably said interface is a mask and said mask and said support being configuredto in use substantially seal against the face of said user without substantial pressure thereto and deliver said gases to the nasal cavity and/or oral cavity and/or throat of said user.
• Preferably said desired fixed relation lies at any point within a predeterminedangular range.
• Preferably said means for securing further comprises a friction engagementwhereby said bridge member may be selectively engaged to said nasal mask in saiddesired fixed relation by a friction engagement.
• Preferably said friction engagement comprises an adjustable clamp engaging atleast a first flange of said nasal mask with a second flange on said bridge member in afixed position relative thereto.
• Preferably said clamp comprises a elongate member extending through aperturesin at least said first flange and said second flange whereby the rotation thereof, througha helical thread acting on either said first flange, said second flange, said bridge memberand/or said interface, thereby increasing or decreasing the compressive pressure of saidfirst flange on said second flange and thereby varying the frictional engagement therebetween.
• Preferably said first flange said second flange are flat
• Preferably said first flange and said second flange are conical.
• In a second aspect a CPAP system for delivering gases to a user
     characterised in that
     a user interface communicates said gases to said user according to the deviceclaimed in any of the proceeding claims.
• Preferably said CPAP system is further characterised in that a humidifier in fluid communication with said interface variably humidifiers said gases prior to delivering tosaid patient.
• To those skilled in the art to which the invention relates, many changes inconstruction and widely differing embodiments and applications of the invention willsuggest themselves without departing from the scope of the invention as defined in theappended claims. The disclosures and the descriptions herein are purely illustrative andare not intended to be in any sense limiting.
• The invention consists in the foregoing and also envisages constructions of whichthe following gives examples.
BRIEF DESCRIPTION OF THE DRAWINGS
• One preferred form of the present invention will now be described with referenceto the accompanying drawings in which;
• Figure 1 is a block diagram of a humidified continuous positive airway pressure(system) as might be used in conjunction with the present invention,
• Figure 2 is an illustration of the nasal mask in use according to the preferredembodiment of the present invention,
• Figure 3 shows a perspective view of the mask with cushion,
• Figure 4 is a cutaway view of the mask showing the cushion,
• Figure 5 is a cutaway view of the periphery of the outer membrane,
• Figure 6 is a cutaway view of the periphery of the mask body portion,
• Figure 7 shows the forehead rest in isolation,
• Figure 8 shows the pivoting forehead rest with a locking mechanism,
• Figure 9 is a perspective view of the mask showing the friction engagement,
• Figure 10 is an alternate perspoctive view of the mask showing the frictionengagement, and
• Figure 11 is a cross section view of the friction engagement.
DETAILED DESCRIPTION
• The present invention provides improvements in the delivery of CPAP therapy. In particular a patient interface is described which is quieter for the user to wear and reducesthe side leakage as compared with the prior art It will be appreciated that the patientinterface as described in the preferred embodiment of the present invention can be usedin respiratory care generally or with a ventilator but will now be described below withreference to use in a humidified CPAP system. It will also be appreciated that the presentinvention can be applied to any form of patient interface including, but not limited to,nasal masks, oral masks and mouthpieces.
• With reference to Figure 1 a humidified Continuous Positive Airway Pressure(CPAP) system is shown in which a patient 1 is receiving humidified and pressurisedgases through apatient interface 2 connected to a humidified gases transportation pathwayorinspiratory conduit 3. It should be understood that delivery systems could also be VPAP(Variable Positive Airway Pressure) and BiPAP (Bi-level Positive Airway Pressure) ornumerous other forms of respiratory therapy.Inspiratory conduit 3 is connected to theoutlet 4 of ahumidification chamber 5 which contains a volume ofwater 6.Inspiratoryconduit 3 may contain heating means or heater wires (not shown) which heat the walls ofthe conduit to reduce condensation of humidified gases within the conduit.Humidificationchamber 6 is preferably formed from a plastics material and may have a highly heatconductive base (for example an aluminium base) which is in direct contact with a heaterplate 7 ofhumidifier 8.Humidifier 8 is provided with control means or electroniccontroller 9 which may comprise a microprocessor based controller executing computersoftware commands stored in associated memory.
• Controller 9 receives input from sources such as user input means ordial 10through which a user of the device may, for example, set a predetermined required value(preset value) of humidity or temperature of the gases supplied to patient 1. The controllermay also receive input from other sources, for example temperature and/orflow velocitysensors 11 and 12 throughconnector 13 and heaterplate temperature sensor 14. Inresponse to the user set humidity or temperature value input viadial 10 and the otherinputs, controller 9 determines when (or to what level) to energise heater plate 7 to heatthewater 6 withinhumidification chamber 5. As the volume ofwater 6 withinhumidification chamber 5 is heated, water vapour begins to fill the volume of the chamber above the water's surface and is passed out of thehumidification chamber 5 outlet 4 withthe flow of gases (for example air) provided from a gases supply means orblower 15which enters the chamber throughinlet 16. Exhaled gases from the patient's mouth arepassed directly to ambient surroundings in Figure 1.
• Blower 15 is provided with variable pressure regulating means orvariable speedfan 21 which draws air or other gases throughblower inlet 17. The speed ofvariable speedfan 21 is controlled by electronic controller 18 (or alternatively the function ofcontroller18 could carried out by controller 9) in response to inputs from controller 9 and a user setpredetermined required value (preset value) of pressure or fan speed viadial 19.
Mask
• According to a first embodiment of the present invention the patient interface isshown in Figure 2 as a mask This may be also a nasal mask, a full face mask, a oral maskendotracheal tube, nasal cannula or other breathing assistance interface as are known inthe art. The mask includes ahollow body 102 with an inlet 103 connected to theinspiratory conduit 3. Themask 2 is positioned around the nose of the user 1 with theheadgear 108 secured around the back of the head of the patient 1. The restraining forcefrom theheadgear 108 on thehollow body 102 and theforehead rest 106 ensures enoughcompressive force on themask cushion 104, to provide an effective seal against thepatient's face.
• Thehollow body 102 is constructed of a relatively inflexible material for example,polycarbonate plastic. Such a material would provide the requisite rigidity as well asbeing transparent and a relatively good insulator. The expiratory gases can be expelledthrough a valve (not shown) in the mask, a simple vent (not shown), a further expiratoryconduit (not shown), or any other such method as is known in the art.
Mask Cushion
• Referring now to Figures 3 and 4 in particular, themask cushion 1104 is providedaround the periphery of thenasal mask 1102 to provide an effective seal onto the face ofthe user to prevent leakage. Themask cushion 1104 is shaped to approximately followthe contours of a patient's face. Themask cushion 104 will deform when pressure isapplied by the headgear 1108 to adapt to the individual contours of any particular user. In particular, there is anindented section 1150 intended to fit over the bridge of the user'snose as well as a lessindented section 1152 to seal around the section beneath the noseand above the upper lip.
• In Figure 4 we see that themask cushion 1104 is composed of ainner foam cushion1110 covered by anouter sealing sheath 1112. Theinner cushion 1110 is constructed ofa resilient material for example polyurethane foam, to distribute the pressure evenly alongthe seal around the user's face. Theinner cushion 1110 is located around theouterperiphery 1114 of theopen face 1116 of thehollow body 1102. Similarly theouter sheath1112 may be commonly attached at its base 1113 to theperiphery 1114 and loosely coversover the top of theinner cushion 1110.
• In the preferred embodiment shown in Figures 3-6 the bottom of theinner cushion1110 fits into a generallytriangular cavity 1154 in thehollow body 1102. Thecavity 1154is formed from aflange 1156 running mid-way around the interior of the hollow body.
• Theouter sheath 1112 fits in place over thecushion 1110, holding it in place. Thesheath 1112 is secured by a snap-fit to theperiphery 1114 of the hollow body. In Figures5-6 theperiphery 1114 is shown including anouter bead 1158. Thesheath 1112 includesamatching bead 1159, whereby once stretched around the periphery, the two beads engageto hold the sheath in place.However it will be appreciated the invention is not limited to this form of sealing.
Forehead Rest
• In the preferred embodiment of the present invention the nasal mask 2102 includesa pivoting forehead rest 106 (seen in Figures 2 and 7). The attachment of theforehead rest106 to thehollow body 102 effectively allows theforehead rest 106 to pivot towards andaway from the user but with no lateral movement
• In one form shown in Figure 7, pins 2130 are provided mounted on abase 2132attached to thehollow body 102. Thesepins 2130 are co-axial withincylinders 2131mounted on abridge member 2136.
• At the top end 2142 (around the user's forehead) of thebridge member 2136harnessing slots 2138 are provided which allow straps from the headgear to be insertedto secure the mask to the headgear. For the user's comfort one or moreresilient cushions 2140 are provided underneath thetop end 2142 of thebridge member 2136, which rest onthe forehead of the user. Thecushion 2140 might be constructed of silicon or any foammaterials as is known in the art for providing cushioning.
• In a further embodiment theforehead rest 106 described previously may includea weakenedsection 2130 at its base 2132 which allows the joiningmember 2136 to pivotfrom thehollow body 102. The bridge member extends up to the forehead of the user.In a further alternative the mask may include a vertical upwardly extending inlet. In thiscase themember 2136 is hinged at its base 2132 to either side of the inlet passage. Againthe member would then extend to the forehead.
• In a still further embodiment shown in Figure 8 theforehead rest 106 is shown withthe pivoting action which can be locked in a single position. As before thebridge member136 pivots by virtue of pins from thehollow body 102 co-operating withcylinders 131 onthebridge member 136. The locking action is provided by an engagingclip 200 whichis attached through an aperture at the base of thebridge member 136. The lock andclip200 has a number of ribs which engage with at least two ribs on the interior of the aperturewhich allows it to lock and place it in at least an upper position and a lower position. Inthe upper position thelocking clip 200 is clear of thehallow body 102 and allows thebridge member 136 to pivot freely. In the lower position thelocking pin 200 engages witha cavity on the surface of the saidhollow body 102 which locks saidbridge member 136at a predetermined angular position with respect to saidhollow body 102. In the preferredembodiment this position provides the maximum offset of the upper section of the maskfrom the bridge of the patients nose.
• In a still further embodiment shown in Figures 9 to 11 thebridge member 430according to the present invention is shown including afriction engagement 432 with themask body 434. In this embodiment themask body 434 is shown with anelbow connector436 connected to theinlet conduit 438. Anadjustment knob 440 provided on the side ofthebridge member 432 allows adjustment. With theknob 440 in a loosened position thebridge member 430 may be pivoted to any desired angle with respect to themask body434. Once in the desired position theknob 440 may be configured to a tightened positionwhereby the angle of thebridge member 430 relative to themask body 434 is substantially fixed by virtue of the friction engagement in the pivot parts.Knob 440 may also beconfigured in a partially tightened position whereby the pivot angle may be adjusted byapplying a large force between the two.
• In more detail shown in Figure 11 theknob 440 includes a helical thread engagingwith a reciprocalhelical thread 441 onpin 442 running transversely through thebridgemember 430. The pin also runs through apertures in twoflanges 444, 445 extending upfrom themask body 434 and aninternal flanges 446 from thebridge member 430. In thisfashion thebody flanges 444, 445 andbridge flange 446 may fictionally engage(optionally also with the inner surfaces of the bridge member 430) once theknob 440 isin a tightened position. More preferablywasher 448 is provided between body flanges444,445 andbridge flange 446.Washer 448 improves the friction engagement and maybe formed as a single hard rubber insert, or two separate washers. Adjustment may eitherbe allowed in a finite number of predetermined positions or more preferably may becompletely variable.
• In a further variation the body flange and bridge flange may be conical, or anyother configuration allowing pivoting as well as engagement in a desired relation.
• The features disclosed in the foregoing description, or the followingclaims, or the accompanying drawings, expressed in their specific formsor in terms of a means for performing the disclosed function, or amethod or process for attaining the disclosed result, as appropriate,may, separately, or in any combination of such features, be utilisedfor realising the invention in diverse forms thereof.

Claims (10)

1. A device for delivering a supply of gases to a user comprising:

   a patient interface, in use in fluid communication with said supply of gases,

   a forehead support adapted to pivot about said interface and in use rest on theforehead of a user and means for securing said forehead support in a substantially fixedrelation to said interface and configurable at least in an adjustment mode for selecting adesired fixed relation and a secured mode for securing said desired fixed relation.
2. A device as claimed in claim 1 wherein said interface is a mask and said mask andsaid support being configured to in use substantially seal against the face of said userwithout substantial pressure there to and deliver said gases to the nasal cavity and/or oralcavity and/or throat of said user.
3. A device as claimed in claims 1 or 2 wherein said desired fixed relation lies at anypoint within a predetermined angular range.
4. A device as claimed in claim 3 wherein said means for securing further comprisesa friction engagement whereby said bridge member may be selectively engaged to saidnasal mask in said desired fixed relation by a friction engagement.
5. A device as claimed in claim 4 wherein said friction engagement comprises anadjustable clamp engaging at least a first flange of said nasal mask with a second flangeon said bridge member in a fixed position relative thereto.
6. A device as claimed in claim 5 wherein said clamp comprises a elongate memberextending through apertures in at least said first flange and said second flange wherebythe rotation thereof, through a helical thread acting on either said first flange, said secondflange, said bridge member and/or said interface, thereby increasing or decreasing thecompressive pressure of said first flange on said second flange and thereby varying the frictional engagement there between.
7. A device as claimed in claim 16 wherein said first flange said second flange areflat.
8. A device as claimed in claim 16 wherein said first flange and said second flangeare conical.
9. A CPAP system for delivering gases to a user
      characterised in that
      a user interface communicates said gases to said user according to the deviceclaimed in any of the proceeding claims.
10. A CPAP system as claimed in claim 9 furthercharacterised in that a humidifier influid communication with said interface variably humidifiers said gases prior to deliveringto said patient.

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